Panelless hot-fill plastic bottle

ABSTRACT

A plastic bottle base having a seating ring perpendicular to the bottle axis. A base inner portion extends upward and inward toward a center bottom wall surrounding the axis. A flexible diaphragm portion extends outward from the seating ring to join a heel portion at a substantially horizontal inflection point. The diaphragm portion is sufficiently flexible to respond to changes in bottle volume and vacuum to allow the seating ring to move upward so that the seating ring is above the heel portion of the bottle. A sidewall is defined by a small number of barrel shaped surfaces separated by indented ring segments to form a panelless plastic bottle capable of hot-filling and capping.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of PCT/US2010/033082 filedApr. 30, 2010, which in turn claims benefit to U.S. provisionalapplication 61/175,506 filed May 5, 2009.

BACKGROUND

The present invention is directed to plastic bottles used to containfoods and beverages that are filled and capped at an elevatedtemperature of at least 160° F., and more typically about 185° F. Thepresent invention is particularly directed to such plastic bottles thatare devoid of any vacuum panels in the body and shoulder areas.

Lightweight, thin-walled containers made of thermoplastic materials suchas polyester resin are well known in the container industry. Forexample, polyethylene terephthalate (PET) has a wide range ofapplications in the field of containers for foodstuffs, flavoringmaterials, cosmetics, beverages, and so on. PET can be molded, byorientation-blowing, into transparent thin-walled containers having ahigh stiffness, impact strength and other improved qualities with a highmolding accuracy. In the past, some cold-filled carbonated bottles haveemployed chimes having additional material at the standing ring surface.The formation of such bottles requires either heavy materialdistribution to blow out the ring or some other non-standard formingprocess. Examples of such bottles are to be found in U.S. Pat. Nos.4,780,257; 4,889,752; and 4,927,679. At elevated temperatures, however,such a thickened chime will soften and roll out so such a base isunsuitable for hot-filling.

Strong, transparent and substantially heat resistant containers may beproduced by the biaxial-orientation blow-molding process in which aparison is oriented both laterally and longitudinally in a temperaturerange suitable for such orientation. Heat-set PET containers areparticularly heat resistant. Biaxially-oriented blow-molded containershave greater stiffness and strength as well as improved gas barrierproperties and transparency. Areas of thick accumulations of material,such as the thickened chimes discussed above, may not be sufficientlyoriented to achieve the desired stiffness and strength to resistmovement when subjected to hot-filling operations. The desirability ofavoiding areas having accumulations of material for bottles intended foruse in hot-filling operations is suggested generally by U.S. Pat. Nos.5,585,065 and 5,735,420. However, both these patents resort to anextensive multi-blow heat-treating operation to achieve the desiredproduct.

Garver et al., U.S. Pat. No. 5,067,622, discloses a bottle made of PETthat is expressly configured for hot filled applications. The bottle'sbody sidewall is rigidized against radial and longitudinal vacuumdistortion so that paper labels can be applied to the bottle. Therigidized sidewall is achieved by providing a plurality of radiallyinward, concave ring segments which are spaced apart from one anotherand separated from one another by cylindrically shaped flats or landsegments. In addition, the amorphous threaded mouth of the bottle isrigidized by gussets molded into the bottle at the junction of the neckand shoulder portion of the bottle to resist deformation when the bottleis capped. To accommodate the post capping vacuum, a bulbous vacuumdeformation area is provided in the shoulder adjacent the bottle neck, aplurality of vacuum deformation panels are provided in a frusto-conicalportion of the shoulder, and a further vacuum deformation panel isprovided in the base. As a result, any post capping vacuum is confinedto the specifically designated areas of the bottle and the sidewallremains undistorted. The lack of post capping sidewall distortion isdisclosed to be the result of a critical sizing of the ring segmentsrelative to the land segments in combination, to some extent, with thecrystallinity level, which is disclosed to be greater than 30%. Otherbottles made of PET that have sidewall including spaced ring segmentsdesigned to rigidize the sidewall are disclosed, for example, in U.S.Pat. Nos. 6,929,139; 7,051,890 and 7,296,701. Other bottles made of PETthat have vacuum responsive panels in the sidewall are disclosed, forexample, in U.S. Pat. Nos. 5,704,503; 6,932,230; and 7,243,808.

In the bottles referenced above, the land segments between the spacedindented ring segments are generally formed as right cylindrical or flatsurfaces having a constant radius from a vertical axis of the bottle.Such flat surfaces generally perform satisfactorily when the indentedring segments are sufficiently close together. However, the sidewall canexperience reduced satisfactory performance when the ring segmentsbecome increasingly spaced from each other so that the intervening landscan individually experience an inward deformation resulting in aconcavity or crease. As a result, the vertical extent of each of thelands is generally minimized to diminish the area that might be subjectto such a concave inward deformation, also known as localized paneling.Additionally, special shapes and relationships have also been adoptedfor the indented ring segments to minimize the opportunity for such aconcave inward deformation of a land portion, which can result in arippled appearance for any covering label.

Another problem with bottles having a series of indented ring segmentswith land segments therebetween is the tendency to fail by ovalizationunder vacuum pressures. Depending on the configuration of the indentedring and transition to each land segment, portions of the indented ringmay tend to move radially outward, while other portions of the sameindented ring may tend to move radially inward, resulting in across-section that appears to be more oval than circular. Ovalization ofbottles not only increases the risk of failure, but also can lead tounaesthetic looking bottles. Other attempts have been made to increasethe number of indented ring segments along the sidewall. While eachindented ring added ridgidizes the sidewall to reduce the risksassociated with ovalization and localized paneling, the bottle oftenexperiences axial shortening or compression, like an accordion, for eachadditional indented ring. This is problematic because it can inhibit thevertical stacking of bottles on top of each other and possibly distortor even tear the label affixed to the sidewall due to such axialmovement.

Accordingly, it is an object of the present invention to form a plasticbottle with a sidewall having a plurality of spaced indented ringsegments separating lands that will resist any tendency towardovalization. It is a further object of the present invention to form aplastic bottle with a sidewall having a plurality of spaced indentedring segments that are sized in relation to the lands separated by thering segments so that the lands will resist any tendency toward aconcave inward deformation. It is a further object of the presentinvention to form a plastic bottle with a sidewall having lands with apreferred geometry and maximum size to further separate indented ringsegments to maximize the vacuum resistance of the plastic bottle toovalization and/or localized paneling.

SUMMARY

A molded plastic bottle in its pre-hot fill state can have a basesurrounding a vertical axis that is responsive to changes in pressureand vacuum with the bottle. A sidewall can have a lower edge that iscoupled to the base. The sidewall can extend upward from the base to asidewall upper edge. The sidewall can be devoid of any vacuum responsivepanels. A shoulder portion can be coupled to the sidewall upper edge.The shoulder portion can lead upward and radially inward to a neckportion. The shoulder portion can also be devoid of any vacuumresponsive panels. A finish can be coupled to the neck portion adaptedto receive a closure. The finish can surround an opening leading to theplastic bottle interior. The various portions of such a plastic bottlecan be molded in a single integral unit by various processes, includingtwo-step reheat stretch blow molding of a preform within a mold definingthe outside surface of the various bottle portions.

In one aspect, the base of the plastic bottle can have a continuousseating ring surrounding the vertical axis at a fixed radius. The basecan also have at least a first inner surface coupled interiorly to thecontinuous seating ring that extends upwardly and inwardly from thecontinuous seating ring. The base can also have a diaphragm surfacecoupled exteriorly to the continuous seating ring. The diaphragm surfacecan include an inner edge extending upwardly and outwardly from thecontinuous seating ring. The diaphragm surface can also include an outeredge extending substantially horizontally outwardly. The base portioncan also include a heel portion joining the diaphragm outer edge to thesidewall lower edge. The diaphragm surface can flex upward in responseto any drop of pressure within the bottle. Given a sufficient drop inpressure, the diaphragm surface can flex upward at least until thecontinuous seating ring is situated above the heel portion.

In another aspect, the sidewall of the plastic bottle can be molded tohave an outer surface having at least one land segment bounded byvertically spaced indented ring segments. Each land segment can bedefined by a vertical arc rotated around the vertical axis to form anoutwardly curved surface or outwardly bowed barrel-shaped surface havingan outermost surface defining a maximum label diameter D_(L) of thebottle. Each land segment can be formed to resist any tendency toward aconcave inward deformation in response to any drop of pressure withinthe bottle. The distance between the vertical axis and the closest pointon the indented ring segments to the axis can be between about 0.8 and0.9 times the maximum distance between the vertical axis and theoutermost surface of the land segments. The vertical dimension of theland segments can be such that there are only two of the land segmentsand three of the indented ring segments between the sidewall lower edgeand the sidewall upper edge. The vertical dimension of each land segmentcan be at least 0.49 D_(L). The vertical arc that forms the outwardlycurved surface of each land segment can have a vertical radius R_(A) ofup to 2.45 D_(L). The indented ring depth can be a depth of at least0.08 D_(L). The vertical radius R_(B) of the inwardly curved surface ofthe indented ring segments can be up to 0.02 D_(L). The plastic bottlespreferably molded in its pre-hot fill state to have a sidewall geometrywith one or more of the aforementioned ratios, such that the plasticbottle can be a lighter weight and/or can have a reduced number ofindented ring segments, while having a satisfactory vacuum resistance tolocalized paneling and/or ovalization.

Other features of the present invention and the corresponding advantagesof those features will become apparent from the following discussion ofthe preferred embodiments of the present invention, exemplifying thebest mode of practicing the present invention, which is illustrated inthe accompanying drawings. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention. Moreover, in the figures, likereferenced numerals designate corresponding parts throughout thedifferent views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exterior surface of a bottle moldedin its pre-hot fill state.

FIG. 2 is a perspective view of an exterior surface of another bottlemolded in its pre-hot fill state.

FIG. 3 is a perspective view of an exterior surface of yet anotherbottle molded in its pre-hot fill state.

FIG. 4 is a sectional view of a base of the bottles shown in FIG. 1-FIG.3 molded in its pre-hot fill state.

FIG. 5 is a sectional view of a base of the bottles shown in FIG. 1-FIG.3 when subjected to a vacuum induced by hot-filing and capping of thebottle.

FIG. 6 is a sectional view of a portion of the sidewall of the bottlesshown in FIG. 1 or FIG. 3.

FIG. 7 is a sectional view similar to FIG. 6 of a portion of thesidewall of the bottle shown in FIG. 2.

FIG. 8 is a line graph comparing the vacuum failure pressure of a bottlewith the vertical radius of a curved land segment of the bottle.

DESCRIPTION OF A PREFERRED EMBODIMENT

A bottle 10 is shown in FIGS. 1-3 to include a base 12, which is shownin its initial molded form prior to hot filling. The bottle can appeardifferent in response to the post capping development of a partialvacuum within the bottle after hot filling to accommodate the change involume and pressure. A sidewall 14 having a lower edge 16 is coupled tothe base 12. It will be understood that the word “coupled” is used inthis disclosure to include structures that are simultaneously molded asa single unit, and is not used to suggest necessarily any assembly ofparts subsequent to the formation of those parts. The sidewall 14extends upward from the lower edge 16 to a sidewall upper edge 18. Thesidewall lower edge 16 is shown to include a step 20 defining a loweredge of a label panel 21. The sidewall upper edge 18 is shown to includeanother step 22 defining an upper edge of the label panel 21. A shoulderportion 24 is coupled to the sidewall upper edge 18. The shoulderportion 24 can lead upward and radially inward as shown to a neckportion 26. A finish 28 is generally coupled to the neck portion 26. Thefinish 28 is adapted to receive a closure, not shown. The finish 28 canhave a variety of surface features for engaging a suitable closure. Thefinish 28 generally surrounds an opening 30 leading to the interior ofthe bottle 10. It is to be noted from the figures that neither thesidewall 14 nor the shoulder portion 24 contains any vacuum responsivepanels of the type often found in prior art containers, although vacuumresponsive panels can be found in at least one those areas, incombination with the bottle embodiments described herein, as appreciatedby those skilled in the art. As can be seen from the variationspresented by FIGS. 1-3, a bottle 10 having the desired operativefeatures can take a variety of forms that will allow for a number ofdesign variations.

A base 12, shown in detail in FIG. 4 in the configuration that thebottles 10 are initially molded, can include a heel portion 34 thatextends from the lower edge 16 of the sidewall 14 downward and inward toan inflection point 32. The inflection point 32 can be an outerperimeter of a diaphragm portion 38 extending from the inflection point32 to a continuous seating ring 36. Consequently, the diameter D_(S) ofthe seating ring 36 is generally smaller than the diameter D of thelower edge 16 of the sidewall 14. The seating ring 36 is spaceduniformly outward from a vertical axis Y that is perpendicular to anyunderlying planar surface on which the bottle 10 might be situated priorto the bottle 10 being hot-filled and capped. As a general rule, thevertical axis Y extends upward through the approximate center of theopening 30. The continuous seating ring 36 when initially moldedpreferably contacts any underlying planar surface on which the bottle 10might be situated around the entire circumference of the seating ring36. The heel portion 34 is shown to have a uniform inside verticalradius so that the surface of the heel portion 34 is smooth as shown inFIGS. 1-3, but the surface of the heel portion 34 could be undulating orgrooved or include other surface features. As initially molded, theouter edge of the diaphragm portion 38 at the inflection point 32 ispreferably horizontal and is spaced upward from the plane defined by theseating ring 36.

The base 12, as shown in detail in FIG. 4, can include an inner portion40 that lies wholly within the seating ring 36. The inner portion 40 ofthe base 12 can extend upward and inward toward a center bottom wall 42surrounding the axis Y. The inner portion 40 can include a first conicalsurface section 44 joined to and extending inward from the seating ring36. The inner portion 40 can also include a second conical surfacesection 46 having an outer edge 48 joined to and extending upward andinward from an outer edge of the first conical surface section 44. Aninner edge 48 of the second conical surface section 46 can be joined toan outer edge 50 of an axial portion 52 surrounding the vertical axis Y.The axial portion 52 can included a central downward extension 54. Anaxial ring portion 56 can separate the central downward extension 54from the second conical surface section 46. The inner portion 40 isdesigned to withstand the initial fluid force and temperature of thehot-fill process. The whole of the base 12 is intended to react to thepost capping development of a partial vacuum within the bottle 10 byevolving from the initially molded form, its pre hot-fill state, shownin FIG. 4 to the post filled form shown in FIG. 5 to accommodateentirely the change in volume and pressure.

The post capping vacuum, which develops as the product-filled bottlecools from the filling temperature to an ambient or even refrigeratedtemperature, causes the inner portion 40 of the base 12 to movevertically upward along axis Y. The upward movement of the inner portion40 causes the diaphragm portion 38 to flex from the position shown inFIG. 4 to the position shown in FIG. 5 to the point that the continuousseating ring 36 becomes positioned above the heel portion 34. As aconsequence, the bottle 10, when hot-filled and capped, has an evenwider and more stable base than when empty. In order for the bottle 10to have a satisfactory stability before and after the hot fillingoperation, it is desirable that the continuous seating ring 36 issituated at a radius of between 0.75 R and 0.85 R, where R is the radiusof the diaphragm outer edge 32. If the continuous seating ring 36 issmaller than this specified range, the bottle 10 becomes increasingunstable and difficult to handle during the filling operation. If thecontinuous seating ring 36 is larger than this specified range, theradial dimension of the diaphragm portion 38 is insufficient to providethe necessary change in volume as the product-filled bottle cools fromthe filling temperature to an ambient or even refrigerated temperature.While this base structure 12 can perform in a satisfactory manner inbottles having a variety of sidewall configurations, it is particularlyuseful with the panelless sidewall configuration 14 shown in FIGS. 1-3as well as FIGS. 6 and 7.

With reference to FIGS. 6 and 7, the sidewall 14 of the bottle, in itspre-hot fill state, between the sidewall lower edge 16 and the sidewallupper edge 18 can include an outer surface 60 having at least one landsegment 62 bounded by vertically spaced indented ring segments 64. Eachland segment 62 can be defined by a vertical arc 66, which can be ofconstant or varying radius R_(A), rotated around the vertical axis Y toform an outwardly bowed barrel-shaped or curved surface 68. The labeldiameter D_(L) is defined between the outermost surface 68 of the landsegments 62 situated diametrically opposite from one another through thevertical axis. The curved surface 68 of each land segment 62 can bedimensioned to resist any tendency toward any concave inward deformationof the surface 68 or localized paneling in response to any drop ofpressure within the bottle 10. The vertical radius R_(A) of the curvedsurface 68 of each land segment can be less than or equal to 2.45 D_(L).

The indented ring segments 64 can have arcuate shoulder portions 70 and72 with a vertical radius R_(BL) separated by a concave ring portion 74defined by a vertical radius R_(B). The vertical radii R_(B) and R_(BL)are generally much smaller in absolute value than the vertical radiusR_(A). In one embodiment, the absolute value of the vertical radiusR_(B) can be from 0.2% to 1.4% of the absolute value of the verticalradius R_(A), and the absolute value of the vertical radius R_(BL) canbe from 1% to 6.5% of the absolute value of the vertical radius R_(A)and can be greater than R_(B). The vertical radius R_(B) can be lessthan or equal to 0.02 D_(L). The transition 76 from the upper most orlower most indented ring to the respective sidewall upper or lower edges18, 16 can also be arcuate with a vertical radius R_(T) typicallygreater than the vertical radius R_(BL), having an absolute value from1.5% to 7% of the absolute value of the vertical radius R_(A). Angle ais the inflection angle of the indented ring segment measured from ahorizontal axis that is perpendicular to the vertical axis Y. Angle αcan be 0° to about 25° (preferably 20°), with a smaller angle providingmore sideload resistance and ovalization resistance.

In another embodiment, the distance D_(R) between the vertical axis Yand the closest point 77 on the indented ring segments 64 to the axis Ycan be between about 0.8 and 0.9 times the maximum distance D_(S)between the vertical axis Y and the outermost surface 68 of the landsegments 62. The difference between distances D_(R) and D_(S) is knownas the ring depth 78 of the indented ring segment 64 relative to theoutermost surface 68. A greater ring depth 78 can provide moreresistance to ovalization. The ring depth 78 can be equal to or greaterthan 0.08 D_(L). The effective ring depth 79 is the distance from theclosest point 74 of the indented ring segments 64 to the axis Y to apoint 80 that is defined as the outward tangent point of the verticalradius R_(BL).

The vertical dimension H_(L) is the label panel height measured from thetop of the upper most indented ring segment to the bottom of the lowermost ring segment, or alternatively, between the steps 20, 22 thatdefine the edges of the label panel 21. The vertical dimension H_(S) ofthe land segments 62 can be equal to or greater than 0.49 D_(L). In theillustrated embodiments, the vertical dimension H_(S) of the landsegments 62 can be such that there are only two of the land segments 62and three of the indented ring segments 64 between the sidewall loweredge 16 and the sidewall upper edge 18. It will be appreciated, howeverthat a few additional land segments 62 and indented ring segments 64could be included having the same described character without departingfrom the central concept of having only a small number, no more thanfive, of such land segments 62 separated by the requisite number ofindented ring segments 64 to define the sidewall 14. However, in someinstances it is preferred to at least minimize the number of indentedring segments and maximize the size of the land segments. For everyindented ring segment included in the sidewall, the bottle canundesirably become axially shorter after cooling, and the bottle mayhave an increase axial springiness, like an accordion. This isproblematic because it can inhibit the vertical stacking of bottles ontop of each other and possibly distort or even tear the label affixed tothe sidewall due to such axial movement. Maximizing the size of the landsegments can increase the surface area contact for the label to affix toand may even be more aesthetically pleasing.

Plastic bottles similar to the illustrated embodiments in FIG. 1 wereanalyzed using Finite Element Analysis (FEA). The bottles had an overallvertical distance of 7.663 inches from the top of the finish to thebottom of the base, and a maximum diameter at the outermost surface ofthe land segment of 2.862 inches, each being a constant dimension forall bottles. A ring depth of 0.223 inches, a vertical radius (R_(B)) of0.056 inches, and an inflection angle of 20 degrees were also maintainedconstant for all bottles. The wall thickness of the bottles variedbetween 0.011 inches to 0.02 inches. All of the bottles analyzed hadthree indented ring segments surrounding the two land segments, or 3-2design.

Bottles with a 3-inch label height H_(L) were analyzed at variousvertical radii R_(A): 2.069 inches; 2.713 inches; 4.3 inches; 7 inches;and 1000 inches. Bottles with a 3.22-inch label height H_(L) wereanalyzed at various vertical radii RA: 5.954 inches; 7 inches; 8.388inches; and 10.812 inches. Bottles with a 3.44-inch label height H_(L)were analyzed at various vertical radii RA: 5.954 inches; 7 inches;8.388 inches; and 1000 inches. Bottles with a 3.67-inch label heightH_(L) were analyzed at various vertical radii R_(A): 4.3 inches; 5.954inches; 7 inches; 8.388 inches; 10.812 inches; and 1000 inches. Bottleswith a 4.5-inch label height H_(L) were analyzed at various verticalradii R_(A): 4.3 inches; 5.954 inches; 7 inches; 8.388 inches; 11.899inches; and 1000 inches. Bottles with a 5-inch label height H_(L) wereanalyzed at various vertical radii R_(A): 4.3 inches; 5.954 inches; 7inches; 8.388 inches; and 1000 inches. Bottles with a 1000-inch verticalradius R_(A) represent substantially flat land segments. The bottleswere held in a fixed location along the neck, while the internal vacuumpressure was increased from 0 psig to negative 20 psig. During theanalysis, the temperature of the material was maintained at about 72degrees F. The vacuum was increased until one of two failures occurred:localized paneling along the land segments, or ovalization along theindented ring segments. The vacuum pressure at the instance of failurewas then recorded for each bottle.

FIG. 8 depicts a graph 100 with plotted data from the analysis. TheX-axis 102 of the graph represents the various vertical radii R_(A) ofbottles analyzed on a logarithmic scale, and the Y-axis 104 representsthe vacuum pressure at the instance of failure. There are six trendlines representing the respective bottles with the six different labelheights H_(L): 3-inch (110), 3.22-inch (120), 3.44-inch (130), 3.67-inch(140), 4.5-inch (150), and 5-inch (160). According to the graph 100, thebottles demonstrated a higher failure pressure or greater vacuumresistance when the vertical radius of the land segment (R_(A)) is about7 inches for the bottles having label heights HL 3.44-inch, 3.67-inch,4.5-inch, and 5-inch. If the vertical radius of the land segment islarger (making the land segments more flat), the bottles would have atendency to fail at a lower pressure due to localized paneling. If thevertical radius of the land segment is smaller (making the land segmentsmore bulbous), the bottles would have a tendency to fail at a lowerpressure due to ovalization.

It was surprising that the bottles, across most of label heights H_(L),had superior vacuum resistance performance at approximately the samevertical radius R_(A) of about 7 inches. According to the graph 100,there may also be a more preferred aspect ratio (label height H_(L) tolabel diameter D_(L)), as the vacuum resistance noticeably changesbetween the 3.22-inch bottles (aspect ratio of 1.13) and the 3.44-inchbottles (aspect ratio of 1.20). The 3.22-inch bottles demonstrated alower vacuum resistance, which was probably from failure caused byovalization instead of localized paneling. On the other hand, a highaspect ratio (e.g., 2.3) can make the effective ring depth very shallow,making the bottles more susceptible to ovalization and/or localizedpaneling. Thus, if the aspect ratio is too high (making the landsegments more flat), the container will have a tendency to fail at alower pressure due to localized paneling. On the other hand, if theaspect ratio is too low (making the land segments more bulbous), thecontainer will have a tendency to fail at a lower pressure due toovalization. Because the bottles across most of label heights H_(L) hadunexpected superior vacuum resistance performance at approximately thesame vertical radius R_(A), the vertical radius R_(A) seems lessdependent on the vertical dimensions H_(S) or H_(L), and more dependenton the label diameter D_(L).

The graph 100 further reveals that the bottles having land segments withthe curved surface had far superior vacuum resistance than the bottleshaving land segments with a flat surface (i.e., when the vertical radiusR_(A) is 1000 inches). Results show a vacuum resistance improvement inthe range of about 20% to 55% (average of 38%) of the bottles having thecurved land segments over the bottles having the flat land segments.

Accordingly, the bottles described herein have a sidewall that includesland segments with a preferred curved geometry to increase theresistance to localized paneling, as well as including indented ringsegment configurations sufficient to maintain the resistance toovalization. Within a more desirable aspect ratio range, the verticalradius R_(A) of the curved surface of each land segment can be less thanor equal to 2.45 D_(L) because a larger ratio may cause the bottle to bemore susceptible to localized paneling at a lower vacuum pressure. Thevertical dimension H_(S) of the land segments can be equal to or greaterthan 0.49 D_(L) because a smaller ratio may result in land segments thatare so short that that the bottles are more prone to failure at a lowervacuum pressure caused by ovalization than by localized paneling. Thering depth can be equal to or greater than 0.08 D_(L) because a smallerratio may cause the bottle to be more susceptible to ovalization at alower vacuum pressure.

In one example, a 20-ounce bottle plastic bottle (with a 3-2 design)having an overall vertical distance of 7.663 inches; a label diameterD_(L) of 2.862 inches; a ring depth 78 of 0.223 inches; an indented ringsegment vertical radius R_(B) of 0.056 inches; an arcuate shouldervertical radius R_(BL) of 0.259 inches; an effective ring depth of 0.207inches; an inflection angle of 20 degrees; a vertical radius R_(T) of0.283 inches; a land segment height H_(S) of 1.516 inches; a labelheight H_(L) of 3.670 inches; a land segment vertical radius R_(A) of7.000 inches; and a wall thickness between 0.011 inches to 0.02 inches.The plastic bottle with these dimensions has a relatively light weightof about 31 grams, yet still has a sufficiently high vacuum failurepressure between 6 to 8 psi. Comparable 20-ounce bottles having similarvacuum resistance performance are known to weigh at least 37 grams,primarily from the added material thickness along the sidewall tostrengthen it for satisfactory vacuum failure resistance. Accordingly,the plastic bottles described herein having a sidewall geometry with oneor more of the ratios above can permit the plastic bottle to have alighter weight and/or a reduced number of indented ring segments, whilehaving a satisfactory vacuum failure resistance. The lighter weight(about 16% lighter) of the plastic bottle further reduces the materialcost per bottle.

While these features have been disclosed in connection with theillustrated preferred embodiment, other embodiments of the inventionwill be apparent to those skilled in the art that come within the spiritof the invention as defined in the following claims.

1. A molded plastic bottle in its pre-hot fill state comprising: a basesurrounding a vertical axis, having a portion extending upward to definean outer edge, a sidewall having a lower edge coupled to the outer edgeof the base, the sidewall extending upward from the base to a sidewallupper edge, a shoulder portion coupled to the sidewall upper edge andleading upward and radially inward to a neck portion, a finish coupledto the neck portion adapted to receive a closure, the finish surroundingan opening leading to a plastic bottle interior, the sidewall beingdefined by an outer surface including at least one land segment boundedby vertically spaced indented ring segments, each land segment beingdefined by a vertical arc rotated around the vertical axis to form anoutwardly curved surface having an outermost point to define a maximumlabel diameter D_(L) of said bottle, the outwardly curved surface of theat least one land segment adapted to resist any tendency toward aconcave inward deformation in response to any drop of pressure withinthe bottle.
 2. The plastic bottle of claim 1, wherein the vertical arcforming the outwardly curved surface of the at least one land segmenthas a vertical radius R_(A) of up to 2.45 D_(L).
 3. The plastic bottleof claim 1, wherein each indented ring segment has a depth of at least0.08 D_(L), the indented ring segment depth being a relative distancebetween the vertical axis and the closest point on the indented ringsegments and the maximum distance between the vertical axis and theoutermost point of the outwardly curved surface of the at least one landsegment.
 4. The plastic bottle of claim 1, wherein the at least one landsegment has a vertical distance of at least 0.49 D_(L).
 5. The plasticbottle of claim 1, wherein the indented ring segments are defined by aninwardly curved surface having a vertical radius R_(B).
 6. The plasticbottle of claim 5, further comprising an arcuate shoulder portionjoining the inwardly curved surface of the indented ring segments to theoutwardly curved surface of the at least one land segment, where thearcuate shoulder portion has a vertical radius R_(BL) that is greaterthan the vertical radius
 7. The plastic bottle of claim 5, wherein thevertical radius R_(B) of the inwardly curved surface of the indentedring segments is up to 0.02 D_(L).
 8. The plastic bottle of claim 1,wherein there are only two of the land segments and three of theindented ring segments between the sidewall lower edge and the sidewallupper edge.
 9. The plastic bottle of claim 1, wherein the distancebetween the vertical axis and the closest point on the indented ringsegments to the axis is between 0.8 and 0.9 times the maximum distancebetween the vertical axis and the outermost surface of the at least oneland segment.
 10. The plastic bottle of claim 1, wherein the verticalarc forming the outwardly curved surface of the at least one landsegment has a vertical radius R_(A) of up to 2.45 D_(L), and at leastone of: each indented ring segment has a depth of at least 0.08 D_(L),the indented ring segment depth being a relative distance between thevertical axis and the closest point on the indented ring segments andthe maximum distance between the vertical axis and the outermost pointof the outwardly curved surface of the at least one land segment; andthe at least one land segment has a vertical distance of at least 0.49D_(L).
 11. A molded plastic bottle in its pre-hot fill state comprising:a base surrounding a vertical axis, a sidewall having a lower edgecoupled to the base, the sidewall extending upward from the base to asidewall upper edge, the sidewall being free of any vacuum responsivepanel and including at least one indented ring segment, a shoulderportion coupled to the sidewall upper edge and leading upward andradially inward to a neck portion, a finish coupled to the neck portionadapted to receive a closure, the finish surrounding an opening leadingto a plastic bottle interior, the base being defined by an outer surfaceincluding a seating ring surrounding the vertical axis at a fixedradius, at least a first inner surface coupled interiorly to the seatingring and extending upwardly and inwardly from the seating ring, adiaphragm surface coupled exteriorly to the seating ring, the diaphragmsurface including an inner edge extending upwardly and outwardly fromthe seating ring and an outer edge extending substantially horizontallyoutwardly, and a heel portion joining the diaphragm outer edge to thesidewall lower edge, the diaphragm surface being sufficiently flexibleto permit an upward flexing of the diaphragm surface in response to anydrop of pressure within the bottle at least until the seating ring issituated above the heel portion.
 12. The plastic bottle of claim 11,wherein the inner surface coupled interiorly to the seating ringcomprises a set of circumferentially continuous conical surface sectionsjoined to and extending inward from the seating ring.
 13. The plasticbottle of claim 11, wherein the continuous seating ring is situated at aradius of between 0.75 R and 0.85 R, where R is the radius of thediaphragm outer edge.
 14. The plastic bottle of claim 11, wherein thesidewall is defined by an outer surface including at least one landsegment bounded by two or more indented ring segments, each land segmentbeing defined by a vertical arc rotated around the vertical axis to forman outwardly curved surface having an outermost point to define amaximum label diameter D_(L) of said bottle.
 15. The plastic bottle ofclaim 14, wherein the vertical arc forming the outwardly curved surfaceof the at least one land segment has a vertical radius
 16. The plasticbottle of claim 15, wherein each indented ring segment has a depth of atleast 0.08 D_(L), the indented ring segment depth being a relativedistance between the vertical axis and the closest point on the indentedring segments and the maximum distance between the vertical axis and theoutermost point of the outwardly curved surface of the at least one landsegment.
 17. The plastic bottle of claim 16, wherein the at least oneland segment has a vertical distance of at least 0.49 D_(L).
 18. Amolded plastic bottle in its pre-hot fill state comprising: a basesurrounding a vertical axis, having a portion extending upward to definean outer edge, a sidewall having a lower edge coupled to the outer edgeof the base, the sidewall extending upward from the base to a sidewallupper edge, a shoulder portion coupled to the sidewall upper edge andleading upward and radially inward to a neck portion, a finish coupledto the neck portion adapted to receive a closure, the finish surroundingan opening leading to a plastic bottle interior, the sidewall beingdefined by an outer surface including at least one land segment boundedby vertically spaced indented ring segments, each land segment beingdefined by a vertical arc rotated around the vertical axis to form anoutwardly bowed barrel-shaped surface with an outermost surface defininga maximum label diameter D_(L) of said bottle, said vertical arc havinga vertical radius R_(A) of up to 2.45 D_(L)) the outwardly bowedbarrel-shaped surface of the at least one land segment adapted to resistany tendency toward a concave inward deformation in response to any dropof pressure within the bottle.
 19. The plastic bottle of claim 18,wherein each indented ring segment has a depth of at least 0.08 D_(L),the indented ring segment depth being a relative distance between thevertical axis and the closest point on the indented ring segments andthe maximum distance between the vertical axis and the outermost pointof the outwardly curved surface of the at least one land segment. 20.The plastic bottle of claim 18, wherein the at least one land segmenthas a vertical distance of at least 0.49 D_(L).